This MRSDA K01 requests 3 years support for advanced research training in genetic gerontology and research support to study genetic and environmental influences on psychosocial geriatrics, health behavior, health services use, and aging. The long-term overall goal of the proposed study is to establish the Vietnam Era Twin [VET] Registry s promise for longitudinal health behavior and aging research. The intermediate goal is to conduct a study that points to research directions for health behavior and aging using the VET Registry. Aims 1 and 2 use data from the Swedish Adoption and Twin Survey and Aging (SATSA) and VET studies to evaluate genetic and environmental influences on stability versus change in (a) self-reported health, (b) health services utilization in Sweden and (c) high-risk health behaviors (obesity, smoking, low physical activity, excess alcohol consumption) in aging male and female like-sex twin pairs. Effects of cohort, gender, and medical condition will be controlled. Aim 3 evaluates the influence of psychiatric Hx and history of substance abuse on self-reported health and high-risk health behaviors among VETs. Aim 4 uses prospective data on obesity, smoking and alcohol use to evaluate genetic and environmental influences on persistence and change in health behaviors and the extent to which these are mediated through psychiatric risk factors. Both Registries have four assessments spanning periods 1984-1996 [total N ~ 3,100 like-sex twin pairs] aged 40-80+ [SATSA] and 40-55 [VET]. For Aims 1-2, bi-variate and developmental genetic modeling will evaluate stability and change in self- reported health, health services use and high-risk health behaviors, controlling for gender, cohort and medical conditions. Replicability of SATSA modeling for VETs will be assessed. Aims 3-4, use developmental genetic modeling and include nine year risk factor Hx and psychiatric Hx to evaluate genetic and environmental influences on persistence and change in high-risk health behaviors, mediated through psychiatric risk factors. The training is designed to provide analytical skills in genetic gerontology to be competitive as an independent investigator. The research project will add significantly to the literature on the role of genetics in understanding persistence of high- risk behaviors in the context of aging.